The use of sealing and coating materials with panes of insulating glass is becoming increasingly important in modern buildings. The most popular materials presently used for this purpose are polysulfide raw materials. These materials have shown very satisfactory long term adherence to glass (see, for example, "Adhasion" (1970), 8, pages 287-290, in particular, page 290). Polysulfide materials do, however, have considerable disadvantages. When they are processed, strong odors are likely to occur and, due to the necessity of maintaining them within a particular pH during their hardening process, difficulties arise in their adaptation to the given manufacturing conditions. Moreover, the conventional use of heavy metal oxides such as lead oxide or manganese oxide, as hardeners requires very careful observance of the processing conditions if health hazards are to be avoided. These special handling requirements and the likelihood of mistakes and losses of these expensive binders increase already high building costs.
Attempts have, therefore, been made to use polyurethane binders for this purpose. Permanently-elastic sealing materials based on polyurethanes have already been successfully used in two-component processes and even in one-component processes (see, for example, U.S. Pat. No. 4,153,594) for the protection of buildings. However, for use as composite materials for glass constructions, conventional polyurethane-based sealing materials have not had satisfactory properties. These known materials have shown insufficient adherence to glass, particularly when sunlight strikes the contact surface between sealing material and glass, leading to a severe loss of adherence over time. Attempts to mitigate this problem by applying light absorbent primers, for example, primers containing carbon black, to the surface, before the sealing materials are applied have not been successful. The visual impression of the glass building components which have been sealed off in this manner is, of course, impaired by such a pigmentation.
Another reason for the lack of acceptance of these sealing materials lies in the fact that the polyurethane systems known in the art are also unsuitable for preventing the undesirable diffusion of water vapor into the internal space of the double glass construction. These conventional polyurethane sealing materials have, therefore, hardly achieved any measure of acceptance.
It was, therefore, an object of the present invention to provide novel composite materials based on polyurethanes, which would be able to be used either solvent-free or with only small quantities of solvent and would not have the above-mentioned disadvantages of the known polyurethane systems, for glass constructions.
This object has been achieved by the use of the systems according to the invention.